start.s

AT91RM9200的完整启动代码：包括loader, boot及U-boot三部分均已编译通过！欢迎下载使用！

/*
 *  Copyright (C) 1998	Dan Malek <[e-mail]>
 *  Copyright (C) 1999	Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
 *  Copyright (C) 2000,2001,2002 Wolfgang Denk <[e-mail]>
 *  Copyright (C) 2001  Josh Huber <[e-mail]>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*  U-Boot - Startup Code for PowerPC based Embedded Boards
 *
 *
 *  The processor starts at 0xfff00100 and the code is executed
 *  from flash. The code is organized to be at an other address
 *  in memory, but as long we don't jump around before relocating.
 *  board_init lies at a quite high address and when the cpu has
 *  jumped there, everything is ok.
 */
#include <config.h>
#include <74xx_7xx.h>
#include <version.h>

#include <ppc_asm.tmpl>
#include <ppc_defs.h>

#include <asm/cache.h>
#include <asm/mmu.h>

#include <galileo/gt64260R.h>

#ifndef  CONFIG_IDENT_STRING
#define  CONFIG_IDENT_STRING ""
#endif

/* We don't want the  MMU yet.
*/
#undef	MSR_KERNEL
/* Machine Check and Recoverable Interr. */
#define MSR_KERNEL ( MSR_ME | MSR_RI )

/*
 * Set up GOT: Global Offset Table
 *
 * Use r14 to access the GOT
 */
	START_GOT
	GOT_ENTRY(_GOT2_TABLE_)
	GOT_ENTRY(_FIXUP_TABLE_)

	GOT_ENTRY(_start)
	GOT_ENTRY(_start_of_vectors)
	GOT_ENTRY(_end_of_vectors)
	GOT_ENTRY(transfer_to_handler)

	GOT_ENTRY(__init_end)
	GOT_ENTRY(_end)
	GOT_ENTRY(__bss_start)
	END_GOT

/*
 * r3 - 1st arg to board_init(): IMMP pointer
 * r4 - 2nd arg to board_init(): boot flag
 */
	.text
	.long	0x27051956		/* U-Boot Magic Number		*/
	.globl	version_string
version_string:
	.ascii	U_BOOT_VERSION
	.ascii	" (", __DATE__, " - ", __TIME__, ")"
	.ascii	CONFIG_IDENT_STRING, "\0"

	. = EXC_OFF_SYS_RESET
	.globl	_start
_start:
	li	r21, BOOTFLAG_COLD	/* Normal Power-On: Boot from FLASH */
	b	boot_cold
	sync

	. = EXC_OFF_SYS_RESET + 0x10

	.globl	_start_warm
_start_warm:
	li	r21, BOOTFLAG_WARM	/* Software reboot		*/
	b	boot_warm
	sync

	/* the boot code is located below the exception table */

	.globl	_start_of_vectors
_start_of_vectors:

/* Machine check */
	STD_EXCEPTION(0x200, MachineCheck, MachineCheckException)

/* Data Storage exception.  "Never" generated on the 860. */
	STD_EXCEPTION(0x300, DataStorage, UnknownException)

/* Instruction Storage exception.  "Never" generated on the 860. */
	STD_EXCEPTION(0x400, InstStorage, UnknownException)

/* External Interrupt exception. */
	STD_EXCEPTION(0x500, ExtInterrupt, external_interrupt)

/* Alignment exception. */
	. = 0x600
Alignment:
	EXCEPTION_PROLOG
	mfspr	r4,DAR
	stw	r4,_DAR(r21)
	mfspr	r5,DSISR
	stw	r5,_DSISR(r21)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	li	r20,MSR_KERNEL
	rlwimi	r20,r23,0,16,16		/* copy EE bit from saved MSR */
	lwz	r6,GOT(transfer_to_handler)
	mtlr	r6
	blrl
.L_Alignment:
	.long	AlignmentException - _start + EXC_OFF_SYS_RESET
	.long	int_return - _start + EXC_OFF_SYS_RESET

/* Program check exception */
	. = 0x700
ProgramCheck:
	EXCEPTION_PROLOG
	addi	r3,r1,STACK_FRAME_OVERHEAD
	li	r20,MSR_KERNEL
	rlwimi	r20,r23,0,16,16		/* copy EE bit from saved MSR */
	lwz	r6,GOT(transfer_to_handler)
	mtlr	r6
	blrl
.L_ProgramCheck:
	.long	ProgramCheckException - _start + EXC_OFF_SYS_RESET
	.long	int_return - _start + EXC_OFF_SYS_RESET

	/* No FPU on MPC8xx.  This exception is not supposed to happen.
	*/
	STD_EXCEPTION(0x800, FPUnavailable, UnknownException)

	/* I guess we could implement decrementer, and may have
	 * to someday for timekeeping.
	 */
	STD_EXCEPTION(0x900, Decrementer, timer_interrupt)
	STD_EXCEPTION(0xa00, Trap_0a, UnknownException)
	STD_EXCEPTION(0xb00, Trap_0b, UnknownException)

	. = 0xc00
/*
 * r0 - SYSCALL number
 * r3-... arguments
 */
SystemCall:
	addis	r11,r0,0		/* get functions table addr */
	ori	r11,r11,0		/* Note: this code is patched in trap_init */
	addis	r12,r0,0		/* get number of functions */
	ori	r12,r12,0

	cmplw	0, r0, r12
	bge	1f

	rlwinm	r0,r0,2,0,31		/* fn_addr = fn_tbl[r0] */
	add	r11,r11,r0
	lwz	r11,0(r11)

	li	r20,0xd00-4		/* Get stack pointer */
	lwz	r12,0(r20)
	subi	r12,r12,12		/* Adjust stack pointer */
	li	r0,0xc00+_end_back-SystemCall
	cmplw	0, r0, r12		/* Check stack overflow */
	bgt	1f
	stw	r12,0(r20)

	mflr	r0
	stw	r0,0(r12)
	mfspr	r0,SRR0
	stw	r0,4(r12)
	mfspr	r0,SRR1
	stw	r0,8(r12)

	li	r12,0xc00+_back-SystemCall
	mtlr	r12
	mtspr	SRR0,r11

1:	SYNC
	rfi

_back:

	mfmsr	r11			/* Disable interrupts */
	li	r12,0
	ori	r12,r12,MSR_EE
	andc	r11,r11,r12
	SYNC				/* Some chip revs need this... */
	mtmsr	r11
	SYNC

	li	r12,0xd00-4		/* restore regs */
	lwz	r12,0(r12)

	lwz	r11,0(r12)
	mtlr	r11
	lwz	r11,4(r12)
	mtspr	SRR0,r11
	lwz	r11,8(r12)
	mtspr	SRR1,r11

	addi	r12,r12,12		/* Adjust stack pointer */
	li	r20,0xd00-4
	stw	r12,0(r20)

	SYNC
	rfi
_end_back:

	STD_EXCEPTION(0xd00, SingleStep, UnknownException)

	STD_EXCEPTION(0xe00, Trap_0e, UnknownException)
	STD_EXCEPTION(0xf00, Trap_0f, UnknownException)

        /*
         * On the MPC8xx, this is a software emulation interrupt. It
         * occurs for all unimplemented and illegal instructions.
	 */
	STD_EXCEPTION(0x1000, SoftEmu, SoftEmuException)

	STD_EXCEPTION(0x1100, InstructionTLBMiss, UnknownException)
	STD_EXCEPTION(0x1200, DataTLBMiss, UnknownException)
	STD_EXCEPTION(0x1300, InstructionTLBError, UnknownException)
	STD_EXCEPTION(0x1400, DataTLBError, UnknownException)

	STD_EXCEPTION(0x1500, Reserved5, UnknownException)
	STD_EXCEPTION(0x1600, Reserved6, UnknownException)
	STD_EXCEPTION(0x1700, Reserved7, UnknownException)
	STD_EXCEPTION(0x1800, Reserved8, UnknownException)
	STD_EXCEPTION(0x1900, Reserved9, UnknownException)
	STD_EXCEPTION(0x1a00, ReservedA, UnknownException)
	STD_EXCEPTION(0x1b00, ReservedB, UnknownException)

	STD_EXCEPTION(0x1c00, DataBreakpoint, UnknownException)
	STD_EXCEPTION(0x1d00, InstructionBreakpoint, UnknownException)
	STD_EXCEPTION(0x1e00, PeripheralBreakpoint, UnknownException)
	STD_EXCEPTION(0x1f00, DevPortBreakpoint, UnknownException)

	.globl	_end_of_vectors
_end_of_vectors:

	. = 0x2000

boot_cold:
boot_warm:
	/* disable everything */
	li	r0, 0
	mtspr	HID0, r0
	sync
	mtmsr	0
	bl	invalidate_bats
	sync

#ifdef CFG_L2
	/* init the L2 cache */
	addis	r3, r0, L2_INIT@h
	ori	r3, r3, L2_INIT@l
	sync
	mtspr	l2cr, r3
#endif
#if defined(CONFIG_ALTIVEC) && defined(CONFIG_74xx)
	.long	0x7e00066c
		/*
                 * dssall instruction, gas doesn't have it yet
                 * ...for altivec, data stream stop all this probably
                 * isn't needed unless we warm (software) reboot U-Boot
		 */
#endif

#ifdef CFG_L2
	/* invalidate the L2 cache */
	bl	l2cache_invalidate
	sync
#endif
#ifdef CFG_BOARD_ASM_INIT
	/* do early init */
	bl	board_asm_init
#endif

	/*
	 * Calculate absolute address in FLASH and jump there
	 *------------------------------------------------------*/
	lis	r3, CFG_MONITOR_BASE@h
	ori	r3, r3, CFG_MONITOR_BASE@l
	addi	r3, r3, in_flash - _start + EXC_OFF_SYS_RESET
	mtlr	r3
	blr

in_flash:
	/* let the C-code set up the rest			*/
	/*							*/
	/* Be careful to keep code relocatable !		*/
	/*------------------------------------------------------*/

	/* perform low-level init */
	/* sdram init, galileo init, etc */
	/* r3:	NHR bit from HID0 */

	/* setup the bats */
	bl	setup_bats
	sync

	/*
	 * Cache must be enabled here for stack-in-cache trick.
	 * This means we need to enable the BATS.
	 * This means:
         *   1) for the EVB, original gt regs need to be mapped
	 *   2) need to have an IBAT for the 0xf region,
	 *      we are running there!
         * Cache should be turned on after BATs, since by default
         * everything is write-through.
         * The init-mem BAT can be reused after reloc. The old
         * gt-regs BAT can be reused after board_init_f calls
         * board_pre_init (EVB only).
         */
#if !defined(CONFIG_BAB7xx) && !defined(CONFIG_ELPPC)
	/* enable address translation */
	bl	enable_addr_trans
	sync

	/* enable and invalidate the data cache */
	bl	l1dcache_enable
	sync
#endif
#ifdef CFG_INIT_RAM_LOCK
	bl	lock_ram_in_cache
	sync
#endif

	/* set up the stack pointer in our newly created
	 * cache-ram (r1) */
	lis	r1, (CFG_INIT_RAM_ADDR + CFG_GBL_DATA_OFFSET)@h
	ori	r1, r1, (CFG_INIT_RAM_ADDR + CFG_GBL_DATA_OFFSET)@l

	li	r0, 0		/* Make room for stack frame header and	*/
	stwu	r0, -4(r1)	/* clear final stack frame so that	*/
	stwu	r0, -4(r1)	/* stack backtraces terminate cleanly	*/

	GET_GOT			/* initialize GOT access	*/

	/* run low-level CPU init code     (from Flash)	*/
	bl	cpu_init_f
	sync

	mr	r3, r21

	/* r3: BOOTFLAG */
	/* run 1st part of board init code (from Flash)   */
	bl	board_init_f
	sync

	/* NOTREACHED */

	.globl	invalidate_bats
invalidate_bats:
	/* invalidate BATs */
	mtspr	IBAT0U, r0
	mtspr	IBAT1U, r0
	mtspr	IBAT2U, r0
	mtspr	IBAT3U, r0
	isync
	mtspr	DBAT0U, r0
	mtspr	DBAT1U, r0
	mtspr	DBAT2U, r0
	mtspr	DBAT3U, r0
	isync
	sync
	blr

	/* setup_bats - set them up to some initial state */
	.globl	setup_bats
setup_bats:
	addis	r0, r0, 0x0000

	/* IBAT 0 */
	addis	r4, r0, CFG_IBAT0L@h
	ori	r4, r4, CFG_IBAT0L@l
	addis	r3, r0, CFG_IBAT0U@h
	ori	r3, r3, CFG_IBAT0U@l
	mtspr	IBAT0L, r4
	mtspr	IBAT0U, r3
	isync

	/* DBAT 0 */
	addis	r4, r0, CFG_DBAT0L@h
	ori	r4, r4, CFG_DBAT0L@l
	addis	r3, r0, CFG_DBAT0U@h
	ori	r3, r3, CFG_DBAT0U@l
	mtspr	DBAT0L, r4
	mtspr	DBAT0U, r3
	isync

	/* IBAT 1 */
	addis	r4, r0, CFG_IBAT1L@h
	ori	r4, r4, CFG_IBAT1L@l
	addis	r3, r0, CFG_IBAT1U@h
	ori	r3, r3, CFG_IBAT1U@l
	mtspr	IBAT1L, r4
	mtspr	IBAT1U, r3
	isync

	/* DBAT 1 */
	addis	r4, r0, CFG_DBAT1L@h
	ori	r4, r4, CFG_DBAT1L@l
	addis	r3, r0, CFG_DBAT1U@h
	ori	r3, r3, CFG_DBAT1U@l
	mtspr	DBAT1L, r4
	mtspr	DBAT1U, r3
	isync

	/* IBAT 2 */
	addis	r4, r0, CFG_IBAT2L@h
	ori	r4, r4, CFG_IBAT2L@l
	addis	r3, r0, CFG_IBAT2U@h
	ori	r3, r3, CFG_IBAT2U@l
	mtspr	IBAT2L, r4